In-Depth Study of Short-Circuit Robustness and Protection of 1200 V SiC MOSFETs

This paper presents an in-depth study of short circuit capability of 1200V SiC MOSFETs under different conditions with explanation and design trade-offs from both application and device perspectives. It also provides solutions for over current protection using off-the-shelf driver ICs. A short circuit capability testing circuits is developed. Several design considerations are discussed to ensure the accurate measurement and well controlled test conditions. Testing results indicate that short circuit capability of SiC MOSFET is highly related with drain voltage and gate voltage, but it is not sensitive to case temperature and switching speed. Commercial IGBT drivers with de-sat protection can protect SiC MOSFETs effectively but the driver circuit needs to be optimized to make sure that the total response time of desat protection is short enough to protect SiC MOSFETs. Performance of different off-the-shelf gate drive ICs with de-sat protection functions are compared and the short circuit protection in half bridge configuration are discussed.